Manufacture of articles, such as semiconductor wafers, include various processes requiring precise positioning (alignment) of the article with respect to a processing tool. These processes include measuring, inspecting, monitoring, lithography, etc.
It is known to determine the coarse orientation of a semiconductor wafer by detecting the position of a notch or flat, typically provided on the wafer, while rotating the wafer. Such a method is described for in U.S. Pat. No. 6,038,029 assigned to the assignee of the present application. Another known approach for wafer alignment in semiconductor manufacturing based on detection of the patterned features on a wafer is described in U.S. Pat. Nos. 5,682,242 and 5,867,590 assigned to the assignee of the present application. In this method, the coarse directions of the grid lines on wafer relative to the direction of a reference coordinate system are detected, and then a direction of one of a plurality of directional features on the wafer is determined, thereby providing a location of the grid junction in the reference coordinate system. An alignment technique based on locating the geometrical center of a wafer and of the wafer marker with high accuracy is disclosed in U.S. Pat. No. 6,544,805, assigned to the assignee of the present application.
Various manufacturing or measuring processes are sequentially applied to a plurality of articles progressing on a production line. The articles are thus sequentially mounted on one processing device, and sites of interest (measurement sites) are searched for in each article. However, even in one processing device, it is difficult to determine the positions of the measurement sites, since the respective wafers may have different coordinate values for the measurement sites.
U.S. Pat. No. 6,363,168 describes a method for determining the measurement position on a semiconductor wafer. This method utilizes determination of measurement information regarding a plurality of measurement points on the wafer. The position of each measurement point is expressed by coordinates in a wafer coordinate system defined on the wafer. Then, based on the measurement information, a position of each measurement point on the wafer mounted on the stage is determined. Since the position of each measurement point is expressed by coordinates in the wafer coordinate system, the measurement information including positions can be commonly applied to a plurality of measurement devices.